Police have been granted extra time to question two men on suspicion of conspiracy to rob and murder after they were arrested close to the home of the millionaire soul singer Joss Stone.

The pair, aged 30 and 33, who are from the Manchester area, were arrested close to Stone's farmhouse home in Cullompton, Devon.

Police said the men were initially arrested for possession of offensive weapons and being equipped to steal. Officers have refused to comment on claims that they have recovered swords, rope, a body bag, maps and aerial photographs of her rural property.

Stone said she was "absolutely fine and getting on with life as normal". A representative of 24-year-old said police had been in touch with the singer. She said: "Joss is aware of the arrests and is being kept informed by the police."

A Devon and Cornwall Police spokesman said police attended an address in Cullompton on Monday after residents reported a suspicious vehicle.

The spokesman said: "Officers attended the area at around 10am and subsequently arrested the occupants of a red Fiat Punto. Major crime detectives are continuing to investigate."

Detective Inspector Steve Parker, who is leading the investigation, said: "The two men in custody had in their possession information relating to an individual in the Cullompton area and items which lead us to suspect that they may have intended to commit a criminal offence. Police inquiries continue and the men remain in custody.

"We're unable to say any more at this time but I would like to thank the local residents for reporting the suspicious car.

"Our officers are currently carrying out reassurance patrols and it's important to stress no properties have been burgled and no individuals have been harmed."

It is believed Stone was at the house with friends when the men were seized but neighbour Simon Alsop, a 57-year-old farmer, said Stone was remaining calm.

He said: "She came here for a coffee on Tuesday afternoon and she was all right. She was quite laid back and not in a major panic.

"It all sounds a bit bizarre and very strange. They were in a very small car. It is hard to say whether it was a serious threat or not. Even so, it is quite scary really.

"I know the whole family well and they are very good neighbours. If Joss isn't working she is often here. Joss is never there on her own. She usually has a small entourage of friends."

Florence Webber, 87, whose bungalow is near Stone's house, said: "It is obviously frightening if there are people driving around here with swords and body bags. You don't expect anything like that in a quiet place like this."

Stone was only 16 when she had her first hit – Fell in Love With a Boy – in 2004 and had just turned 17 when she won Brit awards for British female solo artist and British urban act.

Her soulful vocals prompted success in the United States, where she was hailed as "the white Aretha Franklin".

Last month, the Sunday Times Rich List placed Stone, who grew up in Devon, as the fifth wealthiest British and Irish pop star aged under 30, estimating her fortune at £9m.